The present invention relates to a semiconductor device having a ferroelectric substance capacitor, particularly to a structure for high integration.
As high integration and michronization of semiconductor device advance, an occupying area of each part is decreased largely in LSI, and research for providing a semiconductor small and high in reliability is repeated.
In the semiconductor device having the ferroelectric substance capacitor being researched now, a capacitor using an ordinary insulating layer for dielectric substance layer such as a capacitor, called PIP capacitor, having an insulating layer between polysilicon layers, or a capacitor, called MOS capacitor, formed sandwiching a silicon oxide film between a silicon layer and metal is used greatly at the same time in order to detect reverse charge quantity of the ferroelectric substance capacitor and to convert to voltage.
That is, a ferroelectric substance capacitor CFERO and PIP capacitor CPIP are used greatly in series connection as shown in the equivalent circuit of FIG. 7.
Conventionally, in order to realize such the semiconductor device, as shown in FIGS. 8A and 8B, a first capacitor is formed on an element separating insulating film 2 formed on surface of a silicon substrate 1 and a second capacitor of a ferroelectric substance capacitor is formed so as to line with the first capacitor on the upper layer of the element region surrounded by the element separating insulating film 2. The first capacitor and the second capacitor are connected in series through a wiring pattern connected mutually through contact holes.
Here, the first capacitor is constructed by a first electrode 3 of a polysilicon layer formed on the element separating insulating film 2, a first insulating film 4 formed as two layers of a silicon oxide layer and a silicon nitride layer on the upper layer thereof, and a second electrode 5 of a polysilicon layer formed further the upper layer thereof.
The second capacitor is formed on the upper layer of the element region surrounded by the element separating insulating film as a not-common capacity, and the second capacitor includes a first electrode 7, a ferroelectric substance film 8, and a second electrode 9.
The mutual connection of the first and second capacitors is achieved through a wiring pattern 10 connected through contact holes.
Such the capacitor structure has large occupying area and it has been a large problem preventing michronization in LSI.
Further, there has been a problem that an escape route of noise is few so as to receive easily influence of noise as a device as shown in a explanation view of FIG. 9.
Thus, the conventional semiconductor device including the ferroelectric substance capacitor has large occupying area and it has been a large problem to prevent high integration of the device.
Further, the device easily receives influence of noise and it causes malfunction.